Abstract: A UV-LED is disclosed. The UV-LED includes a sapphire substrate, a u-GaN buffer layer formed on the sapphire substrate, an n-GaN contact layer formed on the u-GaN buffer layer, an InGaN light emitting layer formed on the n-GaN contact layer, and a p-GaN layer formed on the InGaN light emitting layer. The UV-LED has a quadrate planar shape with at least one side having a chip size of 50 ?m or less.

Abstract: A UV-LED is disclosed. The UV-LED includes a sapphire substrate, a u-GaN buffer layer formed on the sapphire substrate, an n-GaN contact layer formed on the u-GaN buffer layer, an InGaN light emitting layer formed on the n-GaN contact layer, and a p-GaN layer formed on the InGaN light emitting layer. The UV-LED has a quadrate planar shape with at least one side having a chip size of 50 ?m or less.

Abstract: The present application discloses a composite substrate with a protective layer for preventing metal from diffusing, comprising: a thermally and electrically conductive layer (2) having a melting point of greater than 1000° C., and a GaN mono-crystalline layer (1) located on the thermally and electrically conductive layer (2). At least the side wall of the composite substrate is cladded with a protective layer (3) for preventing metal from diffusing. The composite substrate not only takes account of the homoepitaxy required for GaN epitaxy and improves the quality of the crystals, but also can be used directly to prepare LEDs with vertical structures and significantly reduce costs. The disclosed composite substrate effectively avoids the pollution of experimental instruments by the diffusion and volatilization of a metal material during the growth of MOCVD at high temperature.

Abstract: A method for preparing a composite substrate for GaN growth includes: growing a GaN monocrystal epitaxial layer on a sapphire substrate, bonding the GaN epitaxial layer onto a temporary substrate, lifting off the sapphire substrate, bonding the GaN epitaxial layer on the temporary substrate with a thermally and electrically conducting substrate, shedding the temporary substrate, and obtaining the composite substrate in which the GaN layer having a surface of gallium polarity is bonded to the conducting substrate. If the GaN layer on the sapphire substrate is directly bonded to the conducting substrate, after the sapphire substrate is lifted off, a composite substrate in which a GaN epitaxial layer having a surface of nitrogen polarity is bonded to the conducting substrate. The disclosed composite substrates have homoepitaxy and improved crystal quality; they can be used for forming LED and other devices at greatly reduces costs.

Abstract: A solid-state laser lift-off apparatus comprises: a solid-state laser (1), a light beam shaping lens (3), motors of oscillating mirrors (5,7), oscillating mirrors (4,6), a field lens (9), a movable platform (10), an industrial control computer and control software (8). The light beam shaping lens (3) is behind the solid-state laser (1), shaping the laser beam from the solid-state laser (1) into required shape. The motors of oscillating mirrors (5,7) are in front of the field lens (9), controlling the movement of the oscillating mirrors (4,6) according to the instruction of the control software (8) to implement different light beam scanning paths. A lift-off method for applying the solid-state laser lift-off apparatus uses a small laser spot to perform scanning, and enables damage-free separation of GaN from a sapphire substrate.

Abstract: A method for nondestructive laser lift-off of GaN from sapphire substrates is disclosed. A solid-state laser is used as the laser source. A small laser-spot having a perimeter length of 3 to 1000 micrometers and a distance of two farthest corners or a longest diameter of no more than 400 micrometers is used for laser scanning point-by-point and line-by-line. The energy at the center of the laser-spot is the strongest and is gradually reduced toward the periphery. A nondestructive laser lift-off with a small laser-spot is achieved. The scanning mode of the laser lift-off is improved. Device lift-off can be achieved without the need of aiming. As a result, the laser lift-off process is simplified, and the efficiency is improved while the rejection rate is reduced. The obstacles of the industrialization of the laser lift-off process are removed.

Abstract: An LED emitting light of wavelength mainly 375 nm or below. The LED includes a GaN layer (16), an n-clad layer (20), an AlInGaN buffer layer (22), a light emitting layer (24), a p-clad layer (26), a p-electrode (30), and an n-electrode (32) arranged on a substrate (10). The light emitting layer (24) has a multi-layer quantum well structure (MQW) in which an InGaN well layer and an AlInGaN barrier layer are superimposed. The quantum well structure increases the effective band gap of the InGaN well layer and reduces the light emitting wavelength. Moreover, by using the AlInGaN buffer layer (22) as the underlying layer of the light emitting layer (24), it is possible to effectively inject electrons into the light emitting layer (24), thereby increasing the light emitting efficiency.

Abstract: A light-emitting element using GaN. On a substrate (10), formed are an SiN buffer layer (12), a GaN buffer layer (14), an undoped GaN layer (16), an Si-doped n-GaN layer (18), an SLS layer (20), an undoped GaN layer (22), an MQW light-emitting layer (24), an SLS layer (26), and a p-GaN layer (28), forming a p electrode (30) and an n electrode (32). The MQW light-emitting layer (24) has a structure in which InGaN well layers and AlGaN barrier layers are alternated. The Al content ratios of the SLS layers (20, and 26) are more than 5% and less than 24%. The In content ratio of the well layer in the MQW light-emitting layer (24) is more than 3% and less than 20%. The Al content ratio of the barrier layer is more than 1% and less than 30%. By adjusting the content ratio and film thickness of each layer to a desired value, the light luminous efficiency for wavelength of less than 400 nm is improved.

Abstract: A light-emitting device operating on a high drive voltage and a small drive current. LEDs (1) are two-dimensionally formed on an insulating substrate (10) of e.g., sapphire monolithically and connected in series to form an LED array. Two such LED arrays are connected to electrodes (32) in inverse parallel. Air-bridge wiring (28) is formed between the LEDs (1) and between the LEDs (1) and electrodes (32). The LED arrays are arranged zigzag to form a plurality of LEDs (1) to produce a high drive voltage and a small drive current. Two LED arrays are connected in inverse parallel, and therefore an AC power supply can be used as the power supply.

Abstract: A light-emitting element using GaN. On a substrate (10), formed are an SiN buffer layer (12), a GaN buffer layer (14), an undoped GaN layer (16), an Si-doped n-GaN layer (18), an SLS layer (20), an undoped GaN layer (22), an MQW light-emitting layer (24), an SLS layer (26), and a p-GaN layer (28), forming a p electrode (30) and an n electrode (32). The MQW light-emitting layer (24) has a structure in which InGaN well layers and AlGaN barrier layers are alternated. The Al content ratios of the SLS layers (20, and 26) are more than 5% and less than 24%. The In content ratio of the well layer in the MQW light-emitting layer (24) is more than 3% and less than 20%. The Al content ratio of the barrier layer is more than 1% and less than 30%. By adjusting the content ratio and film thickness of each layer to a desired value, the light luminous efficiency for wavelength of less than 400 nm is improved.

Abstract: A light-emitting apparatus employing a GaN-based semiconductor. The light-emitting apparatus comprises an n-type clad layer (124); an active layer (129) including an n-type first barrier layer (126), well layers (128), and second barrier layers (130); a p-type block layer (132); and a p-type clad layer (134). By setting the band gap energy Egb of the p-type block layer (132), the band gap energy Eg2 of the second barrier layers (130), the band gap energy Eg1 of the first barrier layer (126), and the band gap energy Egc of the n-type and the p-type clad layers such that the relationship Egb>Eg2>Eg1?Egc is satisfied; the carriers can be efficiently confined; and the intensity of the light emission can be increased.

Abstract: A light-emitting apparatus employing a GaN-based semiconductor. The light-emitting apparatus comprises an n-type clad layer (124); an active layer (129) including an n-type first barrier layer (126), well layers (128), and second barrier layers (130); a p-type block layer (132); and a p-type clad layer (134). By setting the band gap energy Egb of the p-type block layer (132), the band gap energy Eg2 of the second barrier layers (130), the band gap energy Eg1 of the first barrier layer (126), and the band gap energy Egc of the n-type and the p-type clad layers such that the relationship Egb>Eg2>Eg1?Egc is satisfied; the carriers can be efficiently confined; and the intensity of the light emission can be increased.

Abstract: For a light emitting device using gallium nitride (GaN), on a substrate are sequentially formed a GaN-based layer, an AlGaN-based layer, and a light emitting layer. To prevent cracks in the AGaN-based layer, the AlGaN-based layer is formed before planarization of the surface of the GaN layer on a surface of the GaN layer which is not planar. For a laser, the AlGaN-based layers serve as clad layers which sandwich the light emitting layer.

Abstract: A GaN-based compound semiconductor device formed by sequentially forming, on a substrate, a GaN-based buffer layer and a GaN-based compound semiconductor layer. AlxGa1-xN1-yPy or AlxGa1-xN1-yAsy (0?x?1, 0<y<1) is used as the GaN-based buffer layer. N in AlxGa1-xN is partially substituted by P or As, whereby a buffer layer is grown at a high temperature. Thus, a difference in processing temperature between the process for growing a buffer layer and processes before and after the process is reduced. The GaN-based compound semiconductor layer formed on the buffer layer comprises a GaN-based layer, an n-type clad layer, a light-emitting layer, and a p-type clad layer. A multiple quantum well (MQW) layer formed from GaNP or GaNAs and GaN is inserted between the GaN-based layers, thereby reducing a dislocation density of the GaN-based layers.

Abstract: A method for manufacturing a nitride semiconductor device in which nitride crystals are sequentially grown on a substrate such as sapphire by MOCVD or the like, and p electrode and n electrode are formed. The wafer is not cut along two perpendicular directions, but rather is cut along two directions that form a 120 degree angle, to obtain a rhombus shaped semiconductor chip. Because the wafer has a six-fold rotation symmetry, by cutting the wafer at an angle of 120 degrees, the cutting directions are equivalent and the wafer can be cut in directions along which it can be easily split.

Abstract: A light-emitting device operating on a high drive voltage and a small drive current. LEDs (1) are two-dimensionally formed on an insulating substrate (10) of e.g., sapphire monolithically and connected in series to form an LED array. Two such LED arrays are connected to electrodes (32) in inverse parallel. Air-bridge wiring (28) is formed between the LEDs (1) and between the LEDs (1) and electrodes (32). The LED arrays are arranged zigzag to form a plurality of LEDs (1) to produce a high drive voltage and a small drive current. Two LED arrays are connected in inverse parallel, and therefore an AC power supply can be used as the power supply.

Abstract: In order to provide a method for easily roughening a surface of a semiconductor constituting an LED, a first material 18 and a second material 20 having a property that they are nonuniformly mixed when thermally treated are deposited on a semiconductor 16, the structure is thermally treated, and etching is performed through reactive ion etching in which the etching rate with respect to the first material 18 is slower than the etching rates with respect to the second material 20 and to the semiconductor 16. During this process, a region 22 in which the first material 18 is the primary constituent functions as an etching mask, and a predetermined roughness can be easily formed on the surface of the semiconductor 16.

Abstract: A method for manufacturing a GaN compound semiconductor which can improve light emitting efficiency even when dislocations are present. An n type AlGaN layer, a undoped AlGaN layer, and a p type AlGaN layer are laminated on a substrate to obtain a double hetero structure. When the undoped AlGaN layer is formed, droplets of Ga or Al are formed on the n type AlGaN layer. The compositional ratio of Ga and Al in the undoped AlGaN layer varies due to the presence of the droplets, creating a spatial fluctuation in the band gap. Because of the spatial fluctuation in the band gap, the percentage of luminous recombinations of electrons and holes is increased.

Abstract: A method for manufacturing a GaN-based semiconductor device in which an ohmic contact can be provided between the semiconductor layer and the electrode material. In a method for manufacturing wherein an n-GaN layer, an emissive layer, a p-GaN layer are formed on a substrate in that order; etching is performed to expose a portion of the n-GaN layer; and a negative electrode is formed on the n-GaN layer, the etching is performed in two sub-steps, an etching step using BCl3 gas and an etching step using Cl2 gas. The surface of the n-GaN layer is exposed in the first sub-step and the B (boron) contamination layer is removed in the second sub-step.

Abstract: A production method of a GaN-based compound semiconductor having excellent crystallinity and a GaN-based semiconductor device produced therefrom. A discrete SiN buffer body is formed on a substrate, and a GaN buffer layer is formed thereon at low temperatures and a GaN semiconductor layer is then formed at high temperatures. By forming the discrete SiN buffer body, the crystal growth, which is dependent on the substrate, of the low-temperature buffer layer is inhibited and monocrystallization is promoted to generate seed crystals used at the time of growing the GaN buffer layer. Further, by forming SiO2 discretely between the substrate and the SiN buffer body or by forming InGaN or a superlattice layer on the GaN semiconductor layer, distortion of the GaN semiconductor layer is reduced.